US President Barack Obama has hailed the death of al-Qaeda leader Osama Bin Laden as a "good day for America," saying the world is now a safer and a better place.

Bin Laden was killed in a raid by US special forces on a compound in the Pakistani city of Abbottabad.

He is believed to have ordered the attacks on New York and Washington on 11 September 2001, as well as a number of other deadly bombings.

He topped the US "most wanted" list.

But his details on the list have now been updated with a simple banner indicating his current status: "Deceased".

DNA tests carried out after the operation indicated with "99.9%" certainty that the man shot dead was Osama Bin Laden, US officials said.

He was buried at sea after a Muslim funeral on board an aircraft carrier in the north Arabian Sea, Pentagon officials said.

President Obama has praised the "heroes" who carried out the operations and in a speech to congressional leaders, called for them to show "the same sense of unity that prevailed on 9/11".

The US has put its embassies around the world on alert, warning Americans of the possibility of al-Qaeda reprisal attacks for Bin Laden's killing.

CIA director Leon Panetta said al-Qaeda would "almost certainly" try to avenge the death of Bin Laden.

The US president's chief counter-terrorism advisor, John Brennan, said that though weakened, al-Qaeda, remained a danger.

"It may be a mortally wounded tiger but it still has some life in it," he said.

Elusive

The UN Security Council also welcomed Bin Laden's death.

In a rare statement on any unilateral military operation by a member country, it said: "The Security Council recognises this critical development and other accomplishments made in the fight against terrorism and urges all states to remain vigilant and intensify their efforts in the fight against terrorism."

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Media captionCounter-Terrorism advisor John Brennan: "The minutes passed like days"

As news of Bin Laden's death was being digested around the world, President Obama said: "Today we are reminded that as a nation there is nothing we can't do".

Later, at a pre-arranged bipartisan dinner at the White House, he appealed for a return to the sense of national unity which he said had "frayed a little" in the years after the 9/11 attacks.

"It is my fervent hope that we can harness some of that unity and some of that pride to confront some of the many challenges that we still face," he said.

On Thursday, Mr Obama will visit New York's Ground Zero, where nearly 3,000 people died in 2001 in the largest attack ever approved by Bin Laden.

The White House said Mr Obama would mark Bin Laden's death by meeting the families of some of those who died.

Bin Laden, 54, evaded the forces of the US and its allies for almost a decade, despite a $25m (£15m) bounty on his head.

On Sunday, US forces said to be from the elite Navy Seal Team Six undertook the operation in Abbottabad, 100km (62 miles) north-east of Islamabad. The raid was reported to have lasted about 40 minutes.

Mr Brennan said US commandos had been ready to take the al-Qaeda leader alive, if that had been possible.

But he was shot in the head after resisting.

Three other men - one of Bin Laden's sons and two couriers - and an unidentified woman, were killed in the raid, the official said.

US officials initially said the woman who died was Bin Laden's wife, but they later said she was only injured.

'Pakistan support'

The compound in Abbottabad is about a kilometre from the Pakistan Military Academy - the country's equivalent of West Point or Sandhurst.

The BBC's Aleem Maqbool in Abbottabad says it will undoubtedly be a huge embarrassment to Pakistan that Bin Laden was found not only in the country, but also on the doorstep of the military academy.

Pakistan was only notified of the operation once US forces had left its airspace.

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Media captionPresident Obama: "We were reminded again that there is a pride in what this nation stands for"

Mr Brennan said it was "inconceivable" that Bin Laden did not have a support system in Pakistan.

"We're going to pursue all leads to find out exactly what type of support system and benefactors that Bin Laden might have had," he said.

However, US Secretary of State Hillary Clinton said co-operation from Pakistan helped lead the Americans to Bin Laden.

Bin Laden's body was consigned to the sea after a funeral service on the USS Carl Vinson.

"The deceased's body was washed and then placed in a white sheet. The body was placed in a weighted bag. A military officer read prepared religious remarks which were translated into Arabic by a native speaker," a US defence official said.

"After the words were complete, the body was placed on a prepared flat board, tipped up, whereupon the deceased's body eased into the sea," the official said.

Photographs of Bin Laden's body have not been released.

The head of the al-Azhar mosque in Cairo, Sunni Islam's most important seat of learning, condemned the decision to dispose of the body at sea.

Grand Imam Sheikh Ahmed al-Tayeb said it was an affront which ran "contrary to the principles of Islamic laws, religious values and humanitarian customs".

As the news spread, crowds gathered outside the White House in Washington DC and Ground Zero, in New York, chanting "USA, USA".

In Pakistan, about 100 people took part in a protest in the western city of Quetta, burning a US flag and chanting anti-American slogans.

Mrs Clinton said the operation sent a signal to the Taliban in both Afghanistan and Pakistan.

"You cannot wait us out, you cannot defeat us, but you can make the choice to abandon al-Qaeda and participate in a peaceful political process," she said.

And she said there was "no better rebuke to al-Qaeda and its heinous ideology" than the peaceful uprisings across the Arab world against authoritarian governments.